This invention relates to a powder level measurement probe and more particularly to a powder level measurement probe which permits the measurement of powder depth in a high pressure, reactive gas-filled, polypropylene gas phase reactor.
The level of polypropylene powder in a stirred gas phase reactor is critical for optimum product quality. Measurement of the powder level within the reactor is extremely difficult due to several reactor characteristics. A reactor pressure of approximately 450 psi together with an operating temperature of 185.degree. F. eliminates the possibility of being able to use commercial bin powder level measurement devices. Additionally, the reactor walls are approximately 21/8 inches thick with an outer steel jacket for steam heating. A further problem associated with the measurement of the powder level within the reactor is that the powder in the reactor is mechanically stirred by a helical screw which precludes access to any level measurement from the sides. Further, the pressure of the gas phase above the powder greatly reduces the effective density difference between the phases.
The physical restraints enumerated above eliminate the use of practically all commercially available devices for powder level measurement. Currently, the most popular type of instrumentation is of the nuclear type but the nuclear type devices suffer from accuracy limitations.
Therefore, it is a principal object of the invention to provide a powder level measurement probe for a polypropylene gas phase reactor.
A further object of the invention is to provide a powder level measurement probe for a polypropylene gas phase reactor which is durable.
A still further object of the invention is to provide a powder level measurement probe for a polypropylene gas phase reactor which includes means for sealing the interior thereof from the reactor.
A still further object of the invention is to provide a powder level measurement probe for a polypropylene gas phase reactor which is extremely accurate.
These and other objects will be apparent to those skilled in the art.